Porous shapes are used in a variety of downhole applications such as for sand control in screens. Such screens are called prepacked screens because they are provided with such porous shapes integrated into a screen assembly. In some cases the presence of the porous material is a substitute for gravel packing the screens downhole. The porous shapes generally involve unitary shapes such as beads to be joined together to form a desired shape.
The way these shapes were made on the past was to coat the beads with a brazing material and feel the beads into a container that represents the desired aggregate shape. That assembly was in turn put into a vacuum furnace and heated while under mechanical compression. This process required specialized equipment and high energy consumption. Accordingly a different process was sought to reduce the cost of manufacturing the porous shapes and that lead to the present invention.
The new method features doing away with the vacuum furnace and replacing that operation with a different way to join the beads or other units into a desired shape. The method focuses on applying nano-layers of material preferably in a fluidized bed CVD furnace. Optionally a brazing material can also be added and the beads or other shapes can be put into a desired final overall shape with sufficient heat added to start the nano-material reacting and creating an exothermic reaction that either alone is sufficient to bond the unit shapes together or, with the aid of the brazing material, accomplishes joining of the unit shapes into a cohesive whole of a desired shape. The process is considerably cheaper to execute from an energy, manpower and specialized equipment cost perspective.
Nano-engineered materials are known as for example NanoFoil® made by Reactive NanoTechnologies of Hunt Valley, Md.; www.rntfoil.com. Once such a material is applied to an object a heat source starts a reaction that is exothermic in the nano-engineered material and the heat generated can be employed to do other things as described in the above mentioned web site.
The following patents are relevant to the discovery and development of the nano-engineered material that is preferred for use in the present invention.
U.S. PAT.NO.Title17,361,412Nanostructured soldered or brazed joints made withreactive multilayer foils27,297,626Process for nickel silicide Ohmic contacts to n-SiC37,143,568Hermetically sealing a container with crushable materialand reactive multilayer material47,121,402Container hermetically sealed with crushable materialand reactive multilayer material56,991,856Methods of making and using freestanding reactivemultilayer foils66,991,855Reactive multilayer foil with conductive and non-conductive final products76,863,992Composite reactive multilayer foil86,736,942Freestanding reactive multilayer foils96,596,101High performance nanostructured materials and methodsof making the same106,534,194Method of making reactive multilayer foil and resultingproduct115,547,715Method for fabricating an ignitable heterogeneousstratified metal structure125,538,795Ignitable heterogeneous stratified structure for thepropagation of an internal exothermic chemical reactionalong an expanding wavefront and method ofmaking same
These and other aspects of the present invention will become more apparent to those skilled in the art from a review of the detailed description of the preferred embodiment and the associated drawings that appear below while recognizing that the full scope of the invention is to be determined by the appended claims.